I was driving home yesterday just coming off the M40 and got stopped at some traffic lights behind a few other cars. Now the specific junction has 4 lanes with two going off onto a dual carriageway which I wanted. We pulled off and the car in the outside two lanes trundelled along the national limit half mile strech at 50. Fair enough I supose, holding me and the car behind you and, as I wanted that lane at the next roundabout, me up as well. No problem, I dropped in behind the two cars then the guy in the middle decided to undertake and drove off somewhere. The car in front of me now drove around the roundabout at 40, hugging the inside the whole way around. I pulled into the outside lane, not increasing my speed at all but then they started to slow down for some reason, so I did the same because they were in front of me and I had no intention of shooting past them on the roundabout. This kept happening as we approached the exit we both wanted, this person clear of my front bumper right up until they started to pull off through my path and came to a full stop. It got to the point where I was also stopped and just looking at them as thy were looking back at me. To be honest I should have just driven past and left myself t think of how much of a moron they were to stop on the inner lane of a roundabout, but I didn’t.

Anyway, they continued to stare at me so I gestured for them to go thinking “You’re in front of me, you have been this entire time and you’re currently in my way, please continue driving before I die of old age”. So now we’re going along at 50 in a 50 limit, perfectly fine. Ahead is a speed camera, I’m personally not worried, we’re doing 50, they clearly are and so slow down to 40 typically. Then after the camera is a nice long stretch of road with this 50 limit which is clearly only there because there are a couple of quite blind junctions onto the road. The person infront of me continues to drive along at 70… why? You were quite happy to drive along at 50 in the 70 limit earlier, why are you now not only breaking the speed limit, but what would and probably should, be the limit (60) if it were unrestricted.

Ridiculous, but I continued to drive along at 50, slowing down to 40 when the next limit came in. Then there is a cross road with a right turn lane and traffic lights, and there in front of me is the same car waiting at the red lights to turn right. So I pulled in behind and waited for the lights, pulled into the road, now with a 30 limit and watch them speed off to around 40mph. Further on, another set of lights, and there they are waiting again, as I pull up the lights go green and out paths separated.

So this got me thinking, that distance, granted only 4.5 miles, took the two of us exactly the same amount of time, and in fact, if I hadn’t been held up on the initial stretch I would have taken less time. So there was a spectrum of speeds we could have used to cover the same distance in the same time. Now this seems like a much more interesting measure of travel. Our two velocities must have been the same, we travelled between the same two points in the same amount of time, and our average speeds must have been the same as we travelled the same overall distance in the same time.

In the “real world” of physics this sort of measurement isn’t really ever thought about, because if you travel the same distance at different speeds your travel time is different, and if you travel for a certain time at different speeds your distance covered is different. Its only when you add in social constructs such as traffic, roundabouts, crossings, traffic lights, etc that this measurement even exists, and if anything it’s a much more accurate measure of congestion and road design than any other. The only issue is that it is incredibly hard to measure. How do you define travelling speeds? Attempt to travel x many miles above the speed limit? Attempt to travel at a set speed? Then the setting off time makes a difference, if you have two miles then a traffic light and travelling at 30 you will get there as it turns red everyone travelling at >30 will get through it and have a faster time to get across it. If you set off a few seconds earlier you’ll likely get across it at 30 as well altering the spectrum further.

Now I think that if you put up signs showing the speed spectrum as well as the limit you’d get people to slow down. If you saw a sign saying the limit was 40, but the speed spectrum is 35-50, meaning if you travel along at 35 you’ll get there at the same time as someone going 50, I’d drive at 40 still, but thats because I’d know the measurement can’t be accurate to my exact case, but if I didn’t understand the measurement I would have driven at 35 to save fuel, the minuscule amount it would be.

Unfortunately I well know that most people would see that and either continue to drive at or below the speed limit per usual, or think, OK, I need to drive at over 50 to get through this faster. This is mainly due to the fact that most people believe they are better than everyone else, and that they deserve to get wherever they’re going faster than anyone else does. This is also the sole reason people run red/changing to red lights, everyone else has to wait, so why don’t you eh?